1. Field of the Invention
The present invention generally relates to an apparatus for facilitating maintenance of a McPherson type strut assembly. More particularly, the present invention relates to a spring-compression apparatus for enabling users thereof to quickly and safely disassemble and reassemble a McPherson type strut assembly.
2. Description of the Prior Art
In order to properly maintain a strut assembly comprising a high tension strut spring, it is necessary to first compress the strut spring so as to remove or otherwise redirect forces away from structure maintaining the strut spring in a spring-compressed state. Once the strut spring is further compressed and forces are redirected, a mounting nut may be removed from the strut assembly and the strut spring may be decompressed to a relaxed state. The strut assembly may then be maintained or repaired as required. A number of apparatuses have been developed with an eye toward facilitating strut spring compression. Some of the more pertinent prior art relating to strut spring compression devices and the like is described hereinafter.
U.S. Pat. No. 3,814,382 ('382 patent), which issued to Castoe, discloses a Spring Compressor. The '382 patent teaches an apparatus for compressing a spring in conjunction with a shock absorber or other similar structure wherein the apparatus includes a frame upon which a spring to be compressed is mounted. An upper yoke member is slidably mounted in the frame and is operatively connected to a power source whereby a bracket is in position to act with a source yoke member to contact a spring being compressed. Downward movement of the yoke causes compression of the spring in a manner that any desired service or operation can be performed on the spring assembly being compressed. The frame further includes a safety mechanism to insure that the spring is safely compressed during service.
U.S. Pat. No. 4,295,634 ('634 patent) and U.S. Pat. No. 4,395,020 ('020 patent), which issued to Spainhour, both disclose a Strut Compressor. The '634 and '020 patents teach a spring compressor employing a fluid operated piston cylinder, which drives a first platen toward a second platen to compress a McPherson type strut mounted between the two platens. The '020 patent further teaches that the first platen may be pivotally mounted for self-adjustment to accommodate many different strut sizes and designs.
U.S. Pat. No. 4,703,547 ('547 patent), which issued to Togawa, discloses an Apparatus for Assembling a Vehicle Suspension Mechanism. The '547 patent teaches an apparatus for assembling a coil spring on a damper strut to manufacture a damper strut assembly. The apparatus includes a clamp for holding the strut in a vertical direction with the lower end of the spring attached to a lower spring seat provided on the strut. A caliper type spring depresser is provided. The depresser is mounted on a plate for movement along a substantially vertical guide rail mechanism. The plate is swingable in a substantially vertical plane so that the direction of movement of the depresser can be adjusted so as to coincide with the direction of the axis of the spring.
U.S. Pat. No. 5,031,294 ('294 patent), which issued to Krueger, discloses a Strut Spring Compressor. The '294 patent teaches an apparatus for use in assembly and disassembly of a strut assembly having a shock absorber disposed within a coil spring. The apparatus includes a frame and a first spring engagement member secured to the frame for engaging the first end of the spring of a strut. A second spring engagement member is provided connected to the frame for movement with the frame toward and away from the first spring engagement member.
U.S. Pat. No. 5,680,686 ('686 patent), which issued to Bosche et al., discloses a Strut Spring Compressor having Floating Compression Head. The '686 patent teaches an apparatus for use in assembling and disassembling a strut assembly of the type having a shock absorber axially disposed within a coil spring including a frame, a first section connected to the frame for supporting the lower portion of the spring, and a second section for holding the upper portion of the spring or upper spring seat. The second section is movable toward and away from the first section and is arranged for axially compressing the spring as the second section moves toward the first section. The second section includes guide structure, a head, linkage structure, and pivot structure. The guide structure is connected to the frame and is for allowing the second section to move toward and away from the first section. The head is mounted on the guide structure and is for positioning the spring. The linkage structure is connected to the guide structure and is for allowing the head to tilt in a first plane generally parallel to the linear axis of the spring. The pivot structure connects the head to the guide structure and is for allowing the head to tilt in a second plane intersecting the first plane.
From an inspection of these patent disclosures and other art generally known in the relevant art, it will be seen that the prior art does not teach a spring compression apparatus comprising a guide rod assembly for guiding the end of a piston rod of a strut assembly when a user reassembles an otherwise disassembled strut assembly. It is noted that the end of a piston rod must be guided through a rod-receiving aperture for receiving a mounting nut, the received mounting nut for maintaining the strut assembly in an assembled, spring-compressed state. The prior art known to exist does not teach this type of spring compression system. Thus, the prior art perceives a need for a spring compression apparatus comprising a guide rod assembly for guiding an end of a piston rod when a user reassembles an otherwise disassembled strut assembly. In this regard, the prior art does not teach structure for guiding the end of a piston rod through a rod-receiving aperture, which aperture is typically sized and shaped for the maintaining the axis of the piston rod, said aperture being critically sized and shaped. Given the high tension of a typical strut spring, it is often quite difficult for assembly workers to reassemble a strut assembly given that the end of the piston rod must be guided through the rod-receiving aperture. Thus, it is contemplated that the present invention is patently distinct from the prior art as summarized in more detail below.